Thin-film magnetic head, method of manufacturing the same, head Gimbal assembly, and hard disk drive

ABSTRACT

A thin-film magnetic head has a laminated construction comprising a main pole layer having a magnetic pole tip on a side of the medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole tip forming a recording gap layer, on the side of the medium-opposing surface, and a thin-film coil wound around at least a portion of the write shield layer. The thin-film magnetic head has an upper yoke pole layer having a larger size than the portion of the main pole layer which is more distant from the medium-opposing surface than the recording gap layer, wherein the upper yoke pole layer is joined to the side of the main pole layer which is near the thin-film coil.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional of application Ser. No. 10/912,245 filed Aug. 6,2004, which in turn claims priority to Provisional Application No.60/580,368, filed on Jun. 18, 2004, which is hereby incorporated byreference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thin-film magnetic head whichperforms magnetic recording operation by a perpendicular recordingsystem, a method of manufacturing the same, a head gimbal assembly andhard disk drive.

2. Related Background Art

Surface recording densities in hard disk drives have improveddramatically in recent years. More particularly, surface recordingdensities in hard disk drives have recently reached 160-200Gbytes/platter, and are poised to exceed even this level. At the sametime, there has been a demand for improved performance of thin-filmmagnetic heads.

Thin-film magnetic heads are largely classified based on their recordingsystems, which may be divided into longitudinal recording systemswherein information is recorded in the (longitudinal) direction withinthe recording surface of the hard disk (recording medium), andperpendicular recording systems wherein the orientation of recordingmagnetization formed on the hard disk is formed in the perpendiculardirection of the recording surface to record data. Of these types ofsystems, perpendicular recording type thin-film magnetic heads arecapable of realizing markedly higher recording density than longitudinalrecording systems, while they also are less susceptible to thermalfluctuation of the recorded hard disk, and are therefore more promisingthan longitudinal recording systems.

Conventional perpendicular recording type thin-film magnetic heads aredisclosed, for example, in U.S. Pat. No. 6,504,675, U.S. Pat. No.4,656,546, U.S. Pat. No. 4,672,493 and Japanese Unexamined PatentPublication No. 2004-94997.

Incidentally, when thin-film magnetic heads of perpendicular recordingsystems accomplish recording of data in the inner and outer perimetersof hard disks, the magnetic pole tip situated on the side of themedium-opposing surface (also referred to air bearing surface, or ABS),which opposes the recording medium (hard disk), forms an angle (skewangle) with the data recording track. When the writing performance ishigh with a perpendicular recording type magnetic head (perpendicularmagnetic recording head: hereinafter also referred to as “PMR”), thisskew angle is responsible for a problem of side fringe, whereby excessdata is recorded between adjacent tracks. When side fringe occurs, itcan adversely affect detection of the servo signal, or the S/N ratio ofthe reproduction waveform. Conventional PMRs therefore have a bevelshape wherein the magnetic pole tip on the ABS side of the main polegradually narrows in width toward one direction. (In this regard, seeJapanese Unexamined Patent Publication No. 2003-242607 and JapaneseUnexamined Patent Publication No. 2003-203311.)

SUMMARY OF THE INVENTION

Conventional PMRs include a thin-film magnetic head 400 having thestructure shown in FIGS. 22(A), (B) and (C), for example. The thin-filmmagnetic head 400 comprises a lower yoke layer 402 which is formed on aninsulating layer 401, and a main pole layer 403 which has beveledmagnetic pole tip disposed at the ABS 404 side, a write shield layer 406magnetically connected with the main pole layer 403, opposite the mainpole layer 403 and sandwiching a recording gap layer 405 on the ABS 404side, and a thin-film coil 407. The thin-film coil 407 is internallyinsulated each other by a photoresist 408, and is wound in a planarspiral fashion around a connecting member 409 which connects the mainpole layer 403 and the write shield layer 406.

In the thin-film magnetic head 400, data recording is accomplished bythe recording gap layer 405. The width W41 near the thin-film coil 407at the ABS 404 of the magnetic pole tip constitutes the track width, andthe hard disk recording density is determined by this width W41. Thethroat height TH is determined by the distance from the ABS 404 of thewrite shield layer 406 to the photoresist 408.

On the other hand, PMRs with narrower track widths such as the thin-filmmagnetic head 400 are desirable for improved recording density. Also, asatisfactory overwrite characteristic is preferred, so that datarecorded on the recording medium is not overwritten by other data.Consequently, a structure is preferred wherein the lower yoke layer 402is as close as possible to the ABS 404.

However, since the thin-film magnetic head 400 has the main pole layer403 formed after the lower yoke layer 402, forming the main pole layer403 with a beveled magnetic pole tip affects the lower yoke layer 402 toproduce a neck height (hn) as shown in the drawing, and this haslengthened the narrow portion of the width corresponding to the trackwidth by the degree of the neck height hn, potentially resulting in ashift from the designed length. Therefore, the lower yoke layer 402 mustbe formed distant from the ABS 404 so that d1 is 0.1-0.3 μm as shown inthe drawing, making it difficult to increase the magnetic charge (alsoknown as magnetic volume) at the location near the ABS 404.Consequently, in a thin-film magnetic head 400, there is a problem whichachieving a satisfactory overwrite characteristic is difficult.

It is an object of the present invention, which has been accomplished inlight of the problems described above, to provide a thin-film magnetichead having a structure which allows a satisfactory overwritecharacteristic to be achieved, as well as a method of manufacturing thesame, a head gimbal assembly and a hard disk drive.

In order to solve the aforementioned problems, the invention provides athin-film magnetic head having a laminated construction comprising amain pole layer having a magnetic pole tip on a side of themedium-opposing surface opposing a recording medium, a write shieldlayer opposing the magnetic pole tip forming a recording gap layer, onthe side of the medium-opposing surface, and a thin-film coil woundaround at least a portion of the write shield layer, and comprising anupper yoke pole layer having a larger size than the portion of the mainpole layer which is more distant from the medium-opposing surface thanthe recording gap layer, wherein the upper yoke pole layer is joined tothe side of the main pole layer which is near the thin-film coil.

The thin-film magnetic head has an upper yoke pole layer, having alarger size than the portion of the main pole layer which is moredistant from the medium-opposing surface than the recording gap layer,joined to the side of the main pole layer which is near the thin-filmcoil.

In the thin-film magnetic head, the write shield layer may also have ashield tip which opposes the magnetic pole tip on the medium-opposingsurface, and formed with the same edge surface height as the upper yokepole layer.

In this thin-film magnetic head, the shield tip absorbs magnetic returnfrom the recording medium.

Preferably, the main pole layer and upper yoke pole layer are formedusing magnetic materials with different saturated flux densities, andthe saturated flux density of the main pole layer is set higher than thesaturated flux density of the upper yoke pole layer.

This will allow the saturated flux density of the magnetic pole tip tobe higher, to avoid saturation of the flux even when the track width ofthe magnetic pole tip is narrowed.

Further, a high tensile strength film made of Ta, W, Mo, TiW, TiN, Cr,NiCr, Mo, Ru or SiN is also preferably provided in contact with the mainpole layer.

The high tensile strength film can maintain the direction of remnantmagnetization of the main pole layer in the direction along themedium-opposing surface after completion of writing.

Also, preferably the shield tip and the upper yoke pole layer are formedusing magnetic materials with different saturated flux densities, andthe saturated flux density of the shield tip is set lower than thesaturated flux density of the upper yoke pole layer.

In addition, an insulating film by AL-CVD may be formed between theshield tip and the upper yoke pole layer.

The upper yoke pole layer may have an enlarged region wherein thelateral width is enlarged at the side near the medium-opposing surface.

The invention further provides a method of manufacturing a thin-filmmagnetic head, wherein a thin-film magnetic head is manufactured bylaminating a main pole layer having a magnetic pole tip on a side of themedium-opposing surface opposing the recording medium, a write shieldlayer opposing the magnetic pole tip forming a recording gap layer, onthe side of the medium-opposing surface, and a thin-film coil woundaround at least a portion of the write shield layer, the method ofmanufacturing a thin-film magnetic head comprising the following steps(1) to (5).

(1) A step of forming a main pole layer on an insulating layer, in sucha manner that it has a magnetic pole tip at the medium-opposing surfaceside,

(2) A step of forming a recording gap layer on the main pole layer, insuch a manner that the section at the side distant from themedium-opposing surface of the main pole layer is exposed,

(3) A step of forming an upper yoke pole layer having a larger size thanthe portion of the main pole layer which is more distant from themedium-opposing surface than the recording gap layer, joined with thelocation not covered by the recording gap layer of the main pole layer,and a shield tip opposing the magnetic pole tip on the medium-opposingsurface, in such a manner that the edge surfaces of each are the sameheight,

(4) A step of forming a thin-film coil in such a manner as to contactthe upper yoke pole layer via the insulating film, and

(5) A step of forming a magnetic shield layer in connection with theshield tip and in connection with the upper yoke pole layer at the sidedistant from the medium-opposing surface, and forming the write shieldlayer comprising the magnetic shield layer and the shield tip.

By carrying out each of these steps, it is possible to obtain athin-film magnetic head wherein the upper yoke pole layer having alarger size than the portion of the main pole layer which is moredistant from the medium-opposing surface than the recording gap layer isjoined to the main pole layer.

There may also be included a step of forming a high tensile strengthfilm between the main pole layer and the insulating layer.

This will allow manufacture of a thin-film magnetic head having a hightensile strength film in contact with the main pole layer.

The method of manufacturing a thin-film magnetic head as described abovemay further include a step of subjecting the surface of the main polelayer to annealing.

By carrying out annealing, it is possible to reduce the effect ofremnant magnetization inside the main pole layer after completion ofwriting.

The invention still further provides a head gimbal assembly comprising athin-film magnetic head formed on a support and a gimbal securing thesupport, wherein the thin-film magnetic head has a laminatedconstruction comprising a main pole layer having a magnetic pole tip ona side of the medium-opposing surface opposing a recording medium; awrite shield layer opposing the magnetic pole tip forming a recordinggap layer, on the side of the medium-opposing surface, and a thin-filmcoil wound around at least a portion of the write shield layer, andcomprising an upper yoke pole layer having a larger size than theportion of the main pole layer which is more distant from themedium-opposing surface than the recording gap layer, wherein the upperyoke pole layer is joined at the side of the main pole layer which isnear the thin-film coil.

The invention still further provides a hard disk device comprising ahead gimbal assembly having a thin-film magnetic head and a recordingmedium opposing the thin-film recording head, wherein the thin-filmmagnetic head has a laminated construction comprising a main pole layerhaving a magnetic pole tip on a side of a medium-opposing surfaceopposing a recording medium, a write shield layer opposing the magneticpole tip forming a recording gap layer, on the side of themedium-opposing surface, and a thin-film coil wound around at least aportion of the write shield layer, and comprising an upper yoke polelayer having a larger size than the portion of the main pole layer whichis more distant from the medium-opposing surface than the recording gaplayer, wherein the upper yoke pole layer is joined to the side of themain pole layer which is near the thin-film coil.

The present invention will be more fully understood from the detaileddescription given hereinbelow and the accompanying drawings which aregiven by way of illustration only, and thus are not to be considered aslimiting the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(A) is a cross-sectional view of a thin-film magnetic headaccording to a first embodiment of the invention, in the directioncrossing the thin-film coil, and FIG. 1(B) is a front view showing theABS.

FIG. 2 is a plan view showing the main pole layer, upper yoke pole layerand write shield layer of a thin-film magnetic head.

FIG. 3 is a perspective view showing the portion of the main pole layerjoined to the upper yoke pole layer.

FIG. 4(A) and FIG. 4(B) are cross-sectional views, corresponding toFIGS. 1(A) and (B), for a step of manufacturing a thin-film magnetichead according to the first embodiment.

FIGS. 5(A) and (B) are cross-sectional views showing the stepssubsequent to FIGS. 4(A) and (B), respectively.

FIGS. 6(A) and (B) are cross-sectional views showing the stepssubsequent to FIGS. 5(A) and (B), respectively.

FIGS. 7(A) and (B) are cross-sectional views showing the stepssubsequent to FIGS. 6(A) and (B), respectively.

FIGS. 8(A) and (B) are cross-sectional views showing the stepssubsequent to FIGS. 7(A) and (B), respectively.

FIG. 9(A) is a cross-sectional view of a thin-film magnetic headaccording to a second embodiment of the invention, in the directioncrossing the thin-film coil, and FIG. 9(B) is a front view showing theABS.

FIGS. 10(A) and (B) are cross-sectional views, corresponding to FIGS.9(A) and (B), for a step of manufacturing a thin-film magnetic headaccording to the second embodiment.

FIGS. 11(A) and (B) are cross-sectional views showing the stepssubsequent to FIGS. 10(A) and (B), respectively.

FIGS. 12(A) and (B) are cross-sectional views showing the stepssubsequent to FIGS. 11(A) and (B), respectively.

FIGS. 13(A) and (B) are cross-sectional views showing the stepssubsequent to FIGS. 12(A) and (B), respectively.

FIGS. 14(A) and (B) are illustrations showing a modification to thethin-film magnetic head of the first embodiment of the invention,wherein FIG. 14(A) is a cross-sectional view and FIG. 14(B) is a frontview showing the ABS.

FIGS. 15(A) and (B) are illustrations showing another modification tothe thin-film magnetic head of the first embodiment of the invention,wherein FIG. 15(A) is a cross-sectional view and FIG. 15(B) is a frontview showing the ABS.

FIGS. 16(A) and (B) are illustrations showing a modification to thethin-film magnetic head of the first embodiment of the invention,wherein FIG. 16(A) is a cross-sectional view and FIG. 16(B) is a frontview showing the ABS. FIG. 16(C) is a plan view showing the main polelayer and upper yoke pole layer, together with the direction of internalmagnetization.

FIG. 17 is a cross-sectional view of a thin-film magnetic head accordingto a third embodiment of the invention, in the direction crossing thethin-film coil.

FIG. 18 is a cross-sectional view, corresponding to FIG. 17, for a stepof manufacturing a thin-film magnetic head according to the thirdembodiment.

FIG. 19 is a cross-sectional view showing the step subsequent to FIG.18.

FIG. 20 is a plan view showing the main pole layer of a thin-filmmagnetic head, and a different upper yoke pole layer and write shieldlayer.

FIG. 21 is a perspective view of a hard disk drive provided with athin-film magnetic head according to the first embodiment of theinvention.

FIGS. 22(A) and (B) are illustrations of a conventional thin-filmmagnetic head, wherein FIG. 22(A) is a cross-sectional view and FIG.22(B) is a front view showing the ABS.

DETAILED DESCRIPTION OF THE REFERRED EMBODIMENTS

Embodiments of the present invention will now be explained in greaterdetail with reference to the accompanying drawings. Constituentsidentical to each other will be referred to with numerals identical toeach other without repeating their overlapping explanations.

First Embodiment (Structure of Thin-Film Magnetic Head)

The structure of a thin-film magnetic head according to the firstembodiment of the invention will be explained first, with reference toFIGS. 1 to 3. FIG. 1(A) is a cross-sectional view of a thin-filmmagnetic head 300 according to a first embodiment of the invention, inthe direction crossing the thin-film coil, and FIG. 1(B) is a front viewshowing the ABS, FIG. 2 is a plan view showing the main pole layer 10,upper yoke pole layer 20 and first shield section 41 of the thin-filmmagnetic head 300, and FIG. 3 is a perspective view showing the joiningportion of the main pole layer 10 and the upper yoke pole layer 20.

The thin-film magnetic head 300 according to the first embodiment is aperpendicular recording type magnetic head having an ABS 30 as themedium-opposing surface opposing the recording medium (hard disk), andit comprises a substrate, a reproduction head with an MR element(magnetoresistance effect element), etc. laminated on the substrate, andrecording head. FIGS. 1(A) and (B) show the recording head laminated onan insulating layer 1, but the substrate and reproduction head are notshown. The construction of the essential parts of the thin-film magnetichead 300 is explained below, while the construction of the other partswill be explained afterwards in connection with the manufacturing steps.

The recording head comprises a main pole layer 10, an upper yoke polelayer 20, a recording gap layer 24, a write shield layer 40 and athin-film coil 100, and is constructed with these elements laminated onthe insulating layer 1 on the substrate, which is not shown.

The main pole layer 10 has a magnetic pole tip 11 and a yoke section 12.The main pole layer 10 has a narrow track width structure wherein thelateral width W1 of the pole tip 11 described hereunder is narrowed, inorder to give the thin-film magnetic head 300 a high data recordingdensity, and a magnetic material (Hi-Bs material) with a highersaturated flux density than the upper yoke pole layer 20 is used so thatthe flux will not be saturated even with a narrowed track widthstructure (this will be described in detail hereunder).

The magnetic pole tip 11 is situated at the ABS 30 side, and comprises atrack width specifier with a fixed width which specifies the trackwidth. As shown in FIG. 1B, the magnetic pole tip 11 at the ABS 30 has alateral width W1 near the thin-film coil 100 in the direction along theABS 30 and a lateral width W2 distant from the thin-film coil 100, andhas a beveled shape such that its lateral width gradually narrows withthe distance from the thin-film coil 100 (W1>W2, where the lateral widthW1 is the track width). The depth of the magnetic pole tip 11 (thedistance from the ABS 30) corresponds to the throat height TH. (For thisembodiment, the throat height TH is about 0.1-0.3 μm, and preferably 0.2μm.)

The yoke section 12 is the section of the main pole layer 10 which ismore distant from the ABS 30 than the recording gap layer 24, and it issituated at a location more distant from the ABS 30 than the magneticpole tip 11. The yoke section 12 has a variable width region wherein thewidth gradually widens with increasing distance from the ABS 30 and afixed width region whose width is fixed, and the upper yoke pole layer20 is joined to the surface at the side near the thin-film coil 100.

The upper yoke pole layer 20 is situated at a position distant from theABS 30 by a depth D (about 0.5-1.0 μm) and comprises a variable widthregion 21 wherein the lateral width gradually widens with increasingdistance from the ABS 30 and a fixed width region 22 which having afixed lateral width, and its overall size (area) is larger than the sizeof the yoke section 12. Also, the upper yoke pole layer 20 is joined tothe surface of the yoke section 12 at the side near the thin-film coil10, so that the yoke section 12 is housed internally. That is, the upperyoke pole layer 20 is joined to the yoke section 12 in such a mannerthat the peripheral section is situated outward from the yoke section12. The lateral width W3 of the section protruding outward from the yokesection 12 is approximately 0.5 μm.

Also, the upper yoke pole layer 20 is magnetically connected with thewrite shield layer 40 at the section distant from the ABS 30, forming alink section 44 with the write shield layer 40.

The recording gap layer 24 is formed between the main pole layer 10 andthe first shield section 41 (described hereunder) of the write shieldlayer 40.

The write shield layer 40 has a first shield section 41, a second shieldsection 42 and a third shield section 43. The first shield section 41 isthe shield tip according to the invention, and it is formed opposing themagnetic pole tip 11 of the main pole layer 10 via the recording gaplayer 24, with the throat height TH determined by the depth in thedirection crossing the ABS 30 (see FIG. 2). Also, the first shieldsection 41 has an edge surface 41 a which is formed to the same heightas the edge surface 20 a at the side of the upper yoke pole layer 20near the thin-film coil 100 (see FIG. 2), and the second shield section42 is connected to this edge surface 41 a.

The second shield section 42 is formed in connection with the firstshield section 41 and the upper yoke pole layer 20 from the side nearthe thin-film coil 100, and has a height equal to the thickness of thethin-film coil 100. The third shield section 43 is formed in connectionwith the second shield section 42, covering the thin-film coil 100 andphotoresist 101 via the insulating layer 32.

The thin-film coil 100 is wound in a planar spiral fashion around thesecond shield section 42, while insulated with respect to the upper yokepole layer 20 and write shield layer 40 via the respective insulatinglayers 31, 32.

The thin-film magnetic head 300 having the construction described abovehas the upper yoke pole layer 20 joined to the surface at the side ofthe main pole layer 10 near the thin-film coil 100, and it is formedafter the main pole layer 10 (described in detail hereunder).Consequently, since the magnetic pole tip 11 is already formed beforethe upper yoke pole layer 20, the upper yoke pole layer 20 is notaffected by the step of forming the magnetic pole tip 11, and thereforeits shape undergoes no change. As a result, the length of the section ofnarrow width having the track width is determined by the magnetic poletip 11 and does not deviate from the designed length, so that the lengthmay be set as projected. The upper yoke pole layer 20 can therefore beformed near the ABS 30. In addition, the upper yoke pole layer 20 has alarger size than the yoke section 12 of the main pole layer 10, and itsmagnetic charge (also known as magnetic volume) is also greater.

Consequently, the thin-film magnetic head 300 may have the upper yokepole layer 20, which has a greater magnetic charge, situated near theABS 30, in order to increase the magnetic charge near the ABS 30. As aresult, the thin-film magnetic head 300 has a construction which permitsa satisfactory overwrite characteristic.

The thin-film magnetic head 300 also has a first shield section 41wherein the upper yoke pole layer 20 and edge face are formed to thesame height, and the first shield section 41 is situated so as to opposethe magnetic tip 11 via the recording gap layer 24 at the ABS 30. Thisfirst shield section 41 can absorb magnetic return from the recordingmedium, to thus prevent leakage of excess magnetism. This allows asatisfactory overwrite characteristic to be maintained even when theupper yoke pole layer 20 is formed near the ABS 30, in order to preventATE (Adjacent Track Erase).

In order to increase the data recording density, the lateral width W1 ofthe magnetic pole tip 11 is narrowed to create a narrow track widthstructure, and the main magnetic pole 10 is formed using a magneticmaterial with a higher saturated flux density than the upper yoke polelayer 20 so that the flux is not saturated.

This will now be explained with reference to FIGS. 16(A), (B) and (C).FIGS. 16(A) and (B) are cross-sectional and front views of thin-filmmagnetic heads 303, 304 manufactured by steps different than for thethin-film magnetic head 300, and FIG. 16(C) is a plan view showing themain pole layer 10 and upper yoke pole layer 20, together with thedirection of internal magnetization. The thin-film magnetic heads 303,304 differ from the thin-film magnetic heads 301, 302 describedhereunder in the sizes of the recording gap layer 24.

In the main pole layer 10, the saturated flux density of the magneticmaterial is higher than the saturated flux density of the upper yokepole layer 20, and therefore it is difficult to reduce themagnetostriction λ. Consequently, even if the direction of magnetizationms is aligned along the direction ABS 30, the orientation of the remnantmagnetization mr of the main pole layer 10 after completion of writingis toward the ABS 30 side and therefore tends to be oriented in anotherdirection which is different from the direction along the ABS.

In the thin-film magnetic head 300, however, since a magnetic materialhaving a lower saturated flux density than the main pole layer 10 can beused for the upper yoke pole layer 20 to reduce the magnetostriction λ,the direction of remnant magnetization of the upper yoke pole layer 20after completion of writing may be prevented from being directed in theanother direction.

Also, since the upper yoke pole layer 20 is joined to the main polelayer 10, the direction of remnant magnetization mr of the main polelayer 10 after completion of writing is corrected by the magnetizationof the upper yoke pole layer 20, and to be prevented from being directedin the another direction as shown in FIG. 16(C).

In other words, by joining the upper yoke pole layer 20 with the mainpole layer 10, the direction of remnant magnetization mr of the mainpole layer 10 after completion of writing is corrected by themagnetization of the upper yoke pole layer 20. Hence, there is noerasure of data already written on the hard disk by leakage flux due toremnant magnetization mr. The thin-film magnetic head 300 can thereforeeffectively prevent appearance of pole erasure while improving recordingdensity. Pole erasure is the phenomenon wherein, after data has beenwritten on a recording medium (hard disk) having a high maximumcoercivity Hc, leakage flux flows from the ABS to the hard disk, even inthe absence of a write current flow to the thin-film coil, thus erasingother data.

(Method of Manufacturing Thin-Film Magnetic Head)

A method of manufacturing the thin-film magnetic head 300 according tothe first embodiment having the construction described above will now beexplained with reference to FIGS. 1(A), (B) to FIG. 3 and FIGS. 4(A),(B) to FIGS. 8(A), (B)

FIGS. 4(A), (B) to FIGS. 8(A), (B) show cross-sectional views ofmanufacturing steps corresponding to FIGS. 1(A), (B), respectively.

In the manufacturing method of this embodiment, first a reproductionhead provided with an MR element (magnetoresistance effect element),etc. is laminated on a substrate (not shown) made of, for example,aluminum oxide/titanium carbide (Al₂O₃.TiC), and an insulating layer 1separating the reproduction head and recording head is formed to athickness of, for example, about 0.2-0.3 μm.

Next, the insulating layer 1 is coated with a photoresist and aprescribed photomask is used for patterning to form a resist patternwith a taper angle of 7-10° on the ABS 30. The resist pattern is usedfor plating with CoFe or CoNiFe as the magnetic material having a highsaturated flux density of 2.3 T-2.4 T to a thickness of about 0.6-0.8μm, to form a main pole layer 10 having a magnetic pole tip 11 at theABS 30 side. The electrode film (not shown) formed for the plating isthen removed, leaving the condition shown in FIGS. 4(A), (B). Theplating is carried out to a thickness of about 0.7 μm.

Next, an insulating section 33 made of alumina (Al₂O₃) is formed to athickness of, for example, 0.5-1.0 μm on the entire surface of thelaminated body, and the surface is polished by chemical mechanicalpolishing (hereinafter “CMP”) so that height (insulating section 33thickness) of main pole layer 10 become about 0.2-0.25 μm, as shown inFIG. 5(A), (B), for surface flattening treatment. This results in thecondition shown in FIG. 5(A), (B), with the insulating section 33situated at a location where the main pole layer 10 is absent.

Either before or after the polishing by CMP, at least the surface ofmagnetic pole tip 11 of the main pole layer 10 may be subjected toannealing at 200-260° C. Annealing can reduce the effect of remnantmagnetization inside the magnetic pole tip 11 after completion ofwriting. The annealing is preferably carried out after formation of therecording gap layer 24 described hereunder.

Next, a coating is formed over the entire top surface of the laminatedbody to 400-500 Å, to form a recording gap layer 24. The material of thecoating may be an insulating material such as alumina or the like, or anon-magnetic metal material such as Ru, NiCu, Ta, W, Cr, Al₂O₃, Si₂O₃ orthe like. The coating is then selectively etched to leave a region atthe ABS 30 side, and expose a section of the side distant from the ABS30 of the main pole layer 10 (the exposed section serving as theaforementioned yoke section 12). This results in formation of arecording gap layer 24 such as shown in FIG. 6(A), (B).

A plating method is used to form the upper yoke pole layer 20 and thefirst shield section 41, in the same step, over the entire surface ofthe laminated body to a thickness of about 0.3-1.0 μm, using NiFe havinga saturated flux density of 1.0-1.6 T or CoNiFe having a saturated fluxdensity of 1.9-2.1 T and a small magnetostriction λ and maximumcoercivity Hc as the magnetic material. The upper yoke pole layer 20 isformed so that it is joined to the location of the main pole layer 10which is not covered with the recording gap layer 24, and so that thefirst shield section 41 is in contact with the ABS 30 side of therecording gap layer 24. The upper yoke pole layer 20 and the firstshield section 41 are formed so that their respective edge surfaces havethe same height in the subsequent steps. Also, the first shield section41 is formed at a position which determines the throat height TH, insuch a manner as to oppose the magnetic pole tip 11 via the recordinggap layer 24 at the ABS 30.

The upper yoke pole layer 20 and first shield section 41 may be formedby a plating method using CoNiFe or NiFe as the magnetic material. Amagnetic material such as FeN, FeCoZrO or FeAlN (each magnetic materialhas a small magnetostriction λ and maximum coercivity Hc and a saturatedflux density of 1.9-2.0 T) is used to form a coating by a sputteringmethod, and the coating may be subjected to reactive ion etching(hereinafter, “RIE”) or ion beam etching (hereinafter, “IBE”).

Next, as shown in FIG. 7(A), (B), an insulating film 34 made of alumina(Al₂O₃) is formed over the entire surface of the laminated body to athickness of, for example, 1.0-1.5 μm. The surface is polished by CMP sothat thickness of first shield section 41 and upper yoke pole layer 20is about 0.3-0.8 μm, for surface flattening treatment. The surfaceflattening treatment produces edge surfaces of the same height for thefirst shield section 41 and upper yoke pole layer 20.

Next, an insulating film made of alumina (Al₂O₃) is formed over theentire surface of the laminated body to a thickness of about 0.2 μm, andan opening is formed at the locations where the second shield section 42is to be formed (a location which can be connected to the first shieldsection 41 and a location which can be connected to the upper yoke polelayer 20). This results in an insulating film 31 for insulation so thatshorting does not occur between the thin-film coil 100 and the upperyoke pole layer 20.

Next, a frame is formed on the insulating film 31, using an electrodefilm (not shown) made of a conductive material and employingphotolithography, and then electroplating is carried out using theelectrode film to form a plating layer made of Cu. The plating layer andthe electrode film below it constitute the thin-film coil 100. Thethin-film coil 100 are formed in contact with the upper yoke pole layer20 via the insulating film 31.

A frame is then formed by photolithography and a second shield section42 serving as the magnetic shield layer of the invention is formed byframe plating (not shown). The second shield section 42 is formed usingthe same magnetic material as for the first shield section 41. Thesecond shield section 42 and the thin-film coil 100 may also be formedin the facing order.

Also, as shown in FIG. 8(A), (B), a photoresist 101 is coated to coverthe entire surface of the laminated body, and an insulating film made ofalumina (Al₂O₃) is formed thereover, after which the entire surface ispolished by CMP for flattening treatment of the surface. In this case,the polishing of the surface by CMP is carried out so that the thicknessof the thin-film coil 100 and second shield section 42 is about 2.0-2.5μm.

Next, an insulating film made of alumina (Al₂O₃) is formed covering theentire surface of the laminated body, to a thickness of about 0.2 μm,and then an opening is formed at the location where the second shieldsection 42 is to be formed. This results in an insulating film 32 forinsulation so that shorting does not occur between the thin-film coil100 and the third shield section 43.

When forming the third shield section 43 serving as the magnetic shieldlayer of the invention, to a thickness of about 2-3 μm, a write shieldlayer 40 is formed opposing the magnetic pole tip 11 via the recordinggap layer 24, in connection with the upper yoke pole layer 20, to obtaina thin-film magnetic head 300 as shown in FIG. 1(A), (B). The thin-filmmagnetic head 300 obtained in this manner, having the constructiondescribed above, is able to exhibit a satisfactory overwritecharacteristic.

Modification Example 1

The manufacturing steps described above may be modified in the followingmanner. Specifically, as shown in FIG. 6(A), (B), after the first shieldsection 41 and upper yoke pole layer 20 have been formed, the thin-filmcoil 100 may be formed via the insulating film 31, before the secondshield section 42. Next, a photoresist 101 may be formed covering thethin-film coil 100. The second shield section 42, serving as themagnetic shield layer of the invention, is then formed covering thephotoresist 101, in connection with the first shield section 41 and theupper yoke pole layer 20. This yields a thin-film magnetic head 301including a write shield layer 40 having a first shield section 41 andsecond shield section 42, not having a third shield section 43, as shownin FIG. 14(A), (B).

This thin-film magnetic head 301 differs from the thin-film magnetichead 300 in that it has no third shield section 43, but it otherwise hasthe same construction and exhibits the same function and effect as thethin-film magnetic head 300. Also, since it does not require a step tomanufacture the third shield section 43 in addition to the second shieldsection 42, the manufacturing steps can be reduced.

Modification Example 2

A tensile film 15 may also be provided in connection with the main polelayer 10, between the insulating layer 1 and the main pole layer 10, asin the thin-film magnetic head 302 shown in FIGS. 15(A) and (B). Thetensile film 15 is a high tensile strength film made of Ta, W, Mo, TiW,TiN, Cr, NiCr or the like, and formed with application of a high tensilestrength of 200 MPa or greater. By providing the tensile film 15 it ispossible to maintain the direction of remnant magnetization mr of themain pole layer 10 after completion of writing in the direction alongthe ABS 30. Thus, the thin-film magnetic head 302 can effectivelyprevent appearance of pole erasure.

Modification Example 3

Also, as shown in FIG. 20, the variable width region 21 of the upperyoke pole layer 20 may be provided with an enlarged region 23 whereinthe lateral width is enlarged at the side near the ABS 30 (W4 shown inFIG. 20 has a width of about 0.5-3.0 μm). Such provision of the enlargedregion 23 in the upper yoke pole layer 20 will allow the magnetic chargeof the upper yoke pole layer 20 to be increased near the ABS 30, so thatthe overwrite characteristic can be even more satisfactory.

Second Embodiment

A thin-film magnetic head according to a second embodiment of theinvention will now be explained with reference to FIG. 9(A), (B). FIG.9(A) is a cross-sectional view of the thin-film magnetic head 310according to the second embodiment of the invention, in the directioncrossing the thin-film coil, and FIG. 9(B) is a front view showing theABS.

(Structure of Thin-Film Magnetic Head)

The thin-film magnetic head 310 according to the second embodiment ofthe invention differs from the thin-film magnetic head 300 describedabove primarily in that it has a tensile film 16 similar to the tensilefilm 15 and in that it has insulating films 35, 36 instead of insulatingfilm 34, but is the same in its other aspects. The differences will nowbe explained, ignoring the aspects which are identical.

The tensile film 16 is formed between the insulating layer 1 and themain pole layer 10, in contact with the main pole layer 10. In thisthin-film magnetic head 310, therefore, the tensile film 16 allows thedirection of remnant magnetization mr of the main pole layer 10 aftercompletion of writing to be maintained in the direction along the ABS30, to effectively prevent appearance of pole erasure. The insulatingfilms 35, 36 are formed at a position of the recording gap layer 24which is more distant from the ABS 30 than the first shield section 41.

Since the thin-film magnetic head 310 having this construction likewisehas the same main pole layer 10 and upper yoke pole layer 20 as thethin-film magnetic head 300, the construction allows the magnetic chargeto be increased near the ABS 30, for a satisfactory overwritecharacteristic.

In addition, since it has the same first shield section 41 as thethin-film magnetic head 300, the first shield section 41 can absorbmagnetic return from the recording medium, to thus prevent leakage ofexcess magnetism. This allows a satisfactory overwrite characteristic tobe maintained, in order to prevent ATE.

(Method of Manufacturing Thin-Film Magnetic Head)

A method of manufacturing the thin-film magnetic head 310 according tothe second embodiment having the construction described above will nowbe explained with reference to FIG. 9(A), (B) and FIG. 10(A), (B) toFIG. 13(A), (B). FIG. 10(A), (B) to FIG. 13(A), (B) show cross-sectionalviews of manufacturing steps corresponding to FIG. 9(A), (B),respectively.

In this embodiment, similar to the first embodiment, an insulating layer1 is formed on a substrate (not shown) to a thickness of, for example,about 0.2-0.3 μm.

Next, as shown in FIG. 10(A), (B), a tensile film 16 is formed to athickness of 500-1000 Å on the insulating layer 1.

Next, the main pole layer 10 comprising the magnetic pole tip 11 andyoke section 12 is formed by the same procedure as the first embodiment.FIG. 9(A), (B) to FIG. 13(A), (B) show the shield layer 17 used forplating to form the main pole layer 10 comprising the magnetic pole tip11 and yoke section 12.

Next, polishing by CMP after formation of the insulating section 33 bythe same procedure as the first embodiment produces a state which aninsulating section 33 fills in the sections where the main pole layer 10is absent, as shown in FIG. 11(A), (B). In this embodiment as well,annealing is carried out in the same manner as the first embodimenteither before or after the polishing by CMP, or after formation of therecording gap layer 24.

Next, as shown in FIG. 12(A), (B), the recording gap layer 24, the firstshield section 41 and the upper yoke pole layer 20 are formed by thesame procedure as the first embodiment.

Also, as shown in FIG. 13(A), (B), a coating made of alumina (Al₂O₃) isformed to 1000-3000 Å by AL-CVD, whereby insulating films 35, 36 areformed filling in the gap between the first shield section 41 and theupper yoke pole layer 20. Since the AL-CVD results in satisfactory stepcoverage, it is possible to form the insulating films 35, 36 in such amanner that no keyhole is formed in the narrow space between the firstshield section 41 and the upper yoke pole layer 20. The insulating films35, 36 may also be coated with alumina (Al₂O₃) formed to a thickness ofabout 0.1-0.5 μm by ALE (Atomic Layer Epitaxy). The alumina (Al₂O₃)insulating films 35, 36 are alumina CVD films formed by alternatingintermittent injection of H₂O, N₂ or N₂O, H₂O₂ and AL(CH₃)₃ or ALCL₃ forforming thin-film, under reduced pressure at a temperature of 180-200°C.

Next, the surface of the insulating films 35, 36 are polished by CMP toa thickness of about 0.3-0.5 μm, and an opening is formed at thelocation where the second shield section 42 is to be formed. This yieldsan insulating film 31. Also, a thin-film coil 100 and second shieldsection 42 are formed by the same procedure as for the first embodiment.

Also, an insulating film 32 made of alumina (Al₂O₃) is formed thereoverto a thickness of 3-4 μm, after which the entire surface is polished byCMP for flattening treatment of the surface. In this case, the polishingof the surface by CMP is carried out so that the thickness of the firstshield section 41 and upper yoke pole layer 20 is about 2.0-2.5 μm. Thesubsequent steps are carried out by the same procedure as for the firstembodiment, to obtain a thin-film magnetic head 310 as shown in FIG.9(A), (B).

Third Embodiment

A thin-film magnetic head according to a third embodiment of theinvention will now be explained with reference to FIG. 17. FIG. 17 is across-sectional view of the thin-film magnetic head 320 according to thethird embodiment of the invention, in the direction crossing thethin-film coil.

(Structure of Thin-Film Magnetic Head)

The thin-film magnetic head 320 according to the third embodiment of theinvention differs from the thin-film magnetic head 310 described aboveprimarily in that it has no tensile film 16 and in that the material ofthe first shield section 41 is different, while it is the same in itsother aspects. The differences will now be explained, ignoring theaspects which are identical.

In the thin-film magnetic heads 300, 310 described above, the upper yokepole layer 20 and first shield section 41 are formed together in thesame step using the same magnetic material, and therefore the saturatedflux density of the magnetic material of the first shield section 41 isthe same as the saturated flux density of the upper yoke pole layer 20.

However, in order to reduce the effect of remnant magnetization aftercompletion of writing, it is preferred for the saturated flux density ofthe first shield section 41 formed at the ABS 30 side to be low. Thefirst shield section 41 and upper yoke pole layer 20 are thereforeformed using different magnetic materials, so that the saturated fluxdensity of the first shield section 41 is at least lower than the mainpole layer 10, and preferably lower than the upper yoke pole layer 20.

The magnetic material of the first shield section 41 may be NiFe with asaturated flux density of 1.6 T, and NiFe with a saturated flux densityof 1.0 T (80%:20%). Alternatively, the magnetic material of the firstshield section 41 may be CoNiFe with a saturated flux density of 1.9 T,and CoFe or CoNiFe having a high saturated flux density of 2.3 T-2.4 Tas the magnetic material of the main pole layer 10, while the saturatedflux density of the upper yoke pole layer 20 may be the same as, orslightly lower than, the main pole layer 10 (for example, about 1.9 T).

(Method of Manufacturing Thin-Film Magnetic Head)

A method of manufacturing the thin-film magnetic head 320 according tothe third embodiment having the construction described above will now beexplained with reference to FIG. 17 above, as well as FIGS. 18 and 19.

As shown in FIGS. 18 and 19, the thin-film magnetic head 320 has a mainpole layer 10 and an insulating layer 33 formed, and a recording gaplayer 24 formed thereover, in the same manner as the second embodiment.Next, as explained above, a magnetic material with a saturated fluxdensity at least lower than the main pole layer 10 and preferably lowerthan the upper yoke pole layer 20 (for example, NiFe with a saturatedflux density of 1.0 T (80%:20%)) is used to form a first shield section41 at a position which determines the throat height TH, so that itopposes the magnetic pole section 11 via the recording gap layer 24 atthe ABS 30.

Next, as shown in FIG. 19, an upper yoke pole layer 20 is formed so thatit is joined to the location of the main pole layer 10 which is notcovered with the recording gap layer 24. The remaining steps are carriedout in the same manner as for the second embodiment.

Incidentally, although the thin-film magnetic head 320 has no tensilefilm 16, it may of course have a tensile film 16 and therefore a stepmay be included of forming a tensile film 16. At least the surface ofthe magnetic pole tip 11 of the main pole layer 10 is subjected toannealing.

The present invention may also be applied for a record-only head havingonly an inductive electromagnetic transducer, or it may be applied for athin-film magnetic head wherein recording and reproduction areaccomplished by an inductive electromagnetic transducer.

(Embodiment of Head Gimbal Assembly and Hard Disk Drive)

An embodiment of a head gimbal assembly and hard disk drive will now beexplained.

FIG. 21 is a perspective view showing a hard disk drive 201 comprisingthe above-mentioned thin-film magnetic head 300. The hard disk drive 201comprises a hard disk (recording medium) 202 rotating at a high speed,and a head gimbal assembly (HGA) 215. The hard disk drive 201 is anapparatus for actuating the HGA 215, so that magnetic information isrecorded onto and reproduced from recording surfaces of the hard disk202. The hard disk 202 comprises a plurality of disks (whose number is 3in the drawing). Each disk has a recording surface opposing thethin-film magnetic head 300. The HGA 215 comprises a gimbal 212 mountedwith a head slider 211 having a support formed with the thin-filmmagnetic head 300 and a suspension arm 213 for supporting the gimbal 212which are disposed on the recording surface of each disk, and isrotatable about a shaft 214 by a voice coil motor which is not depicted,for example. As the HGA 215 is rotated, the head slider 211 movesradially of the hard disk 202, i.e., in directions traversing tracklines.

Since the HGA 215 and hard disk drive 201 have thin-film magnetic heads300, it is possible to achieve a satisfactory overwrite characteristic.An HGA 215 and hard disk drive 201 having thin-film recording headsaccording to the second and third embodiments can likewise achievesatisfactory overwrite characteristics.

It is clear that various embodiments and modified examples of thepresent invention can be carried out on the basis of the foregoingexplanation. Therefore, the present invention can be carried out inmodes other than the above-mentioned best modes within the scopeequivalent to the following claims.

1. A method of manufacturing a thin-film magnetic head, wherein athin-film magnetic head is manufactured by laminating a main pole layerhaving a magnetic pole tip on a side of the medium-opposing surfaceopposing the recording medium, a write shield layer opposing saidmagnetic pole tip forming a recording gap layer, on the side of saidmedium-opposing surface, and a thin-film coil wound around at least aportion of said write shield layer, the method of manufacturing athin-film magnetic head comprising: a step of forming said main polelayer on an insulating layer, in such a manner that it has said magneticpole tip at said medium-opposing surface side, a step of forming saidrecording gap layer on said main pole layer, in such a manner that thesection at the side distant from said medium-opposing surface of saidmain pole layer is exposed, a step of forming an upper yoke pole layerhaving a larger size than the portion of said main pole layer which ismore distant from said medium-opposing surface than said recording gaplayer, joined with the location not covered by said recording gap layerof said main pole layer, and a shield tip opposing said magnetic poletip on said medium-opposing surface, in such a manner that the edgesurfaces of each are the same height, a step of forming said thin-filmcoil in such a manner as to contact said upper yoke pole layer via aninsulating film, and a step of forming a magnetic shield layer inconnection with said shield tip and in connection with said upper yokepole layer at the side distant from said medium-opposing surface, andforming said write shield layer comprising said magnetic shield layerand said shield tip.
 2. A method of manufacturing a thin-film magnetichead according to claim 1, which further comprises a step of forming ahigh tensile strength film between said main pole layer and saidinsulating layer.
 3. A method of manufacturing a thin-film magnetic headaccording to claim 1, which further comprises a step of subjecting thesurface of said main pole layer to annealing.